JPH03254991A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To perform a high-sensitivity recording as well as a high-contrast regeneration using a single pick-up by providing a recording layer containing an organic compound shown by a specific formula on a substrate. CONSTITUTION:An optical information recording medium is formed by providing a recording layer containing an organic compound shown by a formula A-L-B on a substrate. Information can be recorded on the recording layer using an optical change induced by a laser beam irradiation. The recording layer is mainly composed of a dye shown by the formula A-L-B, where A represents a color forming group having an absorption maximum at and around a recording regeneration wavelength; B represents a color forming group having a reflection maximum at and around said wavelength; and L is a substd. or unsubstd. alkylene group. In this manner, a high sensitivity recording and a high-contrast regeneration can be performed at the same time using a single pick-up. In addition, a defect cannot occur even under a long-term storage and, thus, a high-reliable optical information medium is made available.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved optical information recording medium that can be used in the optical recording field.

[Conventional technology]

Until now, optical information recording media have been proposed in which a recording layer made of a low melting point metal or a low melting point metal and a dielectric is provided on a substrate, but these have poor storage stability, low resolution, and recording density. It has disadvantages such as low yield, difficult manufacturing conditions, and high cost. Therefore, it has recently been proposed to use an organic dye thin film as the recording layer in place of the metal thin film. This organic dye thin film has a low melting point, low decomposition temperature, and low thermal conductivity, so it has the potential for high sensitivity and high density, and because film formation can be done by coating, it is highly mass-producible and expected to be low cost. There are advantages such as being able to

Conventionally, it has been known to use a cyanine dye or merocyanine dye coating as the organic dye coating. However, since the maximum absorption wavelength and the maximum reflection wavelength of a recording layer composed of such dyes are different, it is difficult to achieve both high-sensitivity recording and high-contrast reproduction using a single pickup. The problem was that it couldn't be done.

In order to solve this problem, in JP-A-1-113288 and JP-A-178493, a dye having an absorption maximum near the recording and reproducing light wavelength and a dye having a reflection maximum near the same recording and reproducing light wavelength are mixed. Proposals have been made to use it as a recording material, achieving both high-sensitivity recording and high-contrast reproduction.

[Problem to be solved by the invention]

However, the prior art has the following problems to be solved.

In other words, a recording layer that is a mixture of a dye that exhibits an absorption maximum near the wavelength of the recording/reproducing light and a dye that exhibits a reflection maximum near the same wavelength is a mixed system, and due to the poor compatibility of the two dyes, it may cause problems during storage. Crystallization and defects may occur, which could be one of the causes of errors.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical information recording medium that is capable of high-sensitivity recording and high-contrast reproduction using a single pickup and that does not generate defects even under long-term storage.

[Means to solve the problem]

In view of the above-mentioned circumstances, the inventors of the present invention have conducted extensive research and have discovered that the above object can be achieved by using an organic compound shown in Formation (1) below as a recording layer material. The invention was completed.

A -L-B ... (T) (wherein A is a chromophore having an absorption maximum near the wavelength of the recording and reproducing light,
13 represents a chromophore having a reflection maximum near the wavelength 1, and L represents a substituted or unsubstituted alkylene group. ) The optical information recording medium of the present invention is basically constructed by providing a recording layer containing an organic compound represented by the above-mentioned -formation (1) on a substrate, but an undercoat layer may be provided between the substrate and the recording layer. Alternatively, a protective layer may be provided on the second side of the recording layer, and both of these layers may be further provided. Alternatively, the pair of recording media constructed in this manner may be made into an air sun 1-inch structure in which the recording layer is placed inside and sealed with another substrate through a space, or a close contact sandwich structure in which the recording medium is bonded through a protective layer. (
It may also be a laminated structure.

Hereinafter, the materials constituting the optical information recording medium of the present invention and the necessary characteristics of each layer will be specifically explained.

(1) Substrate The necessary characteristics of the substrate are that it must be transparent to the laser beam used only when recording and reproducing are performed from the substrate side, and it does not need to be transparent when recording and reproducing is performed from the recording layer side.

Examples of substrate materials include polyester, acrylic resin,
Plastics such as polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide, glass, ceramic, or metal can be used.

Note that the surface of the substrate may be formed with guide grooves or guide pits for tracking, and also with a brake form I for address signals and the like.

(2) Undercoat layer The undercoat layer (a) improves adhesion, (b) serves as a barrier against water or gas, (c) improves storage stability of the recording layer, and (d)
) direction of reflectance, (e) protection of the substrate from solvents, (f
) Used for the purpose of forming guide grooves, guide pits, preformats, etc. For the purpose of (a), various polymer materials such as ionomer resins, polyamide resins, vinyl resins, natural resins, natural polymers, silicones, liquid rubbers, and silane coupling agents are used. For the purposes (b) and (c), inorganic compounds such as Bi
b2, MgF2, Sin, Tj, 0□, ZnO1Ti
Metals or metalloids such as N, SjN, etc., such as Zn,
Au, S, Nj, Cr, Ge, Se, Au,
Ag, An, etc. can be used. Also, (d)
For this purpose, metals such as AQ, Ag, Te, etc., and organic thin films with metallic luster such as methine dyes,
Xanthine dyes etc. can be used, and (e) and (
For the purpose of f), ultraviolet curing resins, thermosetting resins,
Thermoplastic resin or the like can be used.

(3) Note layer The recording layer causes some kind of optical change by irradiation with laser light, and can record information by that change. A is a chromophore that has an absorption maximum near the recording/reproducing wavelength, B is a chromophore that has a maximum reflection near the above wavelength, and 14 is a substituted or unsubstituted alkylene group. do. ``1. Chromophores include polymethine dye residues, azaannulene dye residues, squarylium residues, croconium residues, pyrylium residues, azulene residues, triphetchazine dye residues, phenanthrene dye residues,
Examples include 1-lahydrocholine dye residues, anthraquinone dye residues, xanthine dye residues, 1-liphenylmethane dye residues, nano-1 hequinone dye residues, and the like. As L, an optionally branched alkylene group having 2 to 12 carbon atoms (dialkylmethylene group, sulfonyl group, imino group, hydroxycarbonyl group, carbonyl group, ether group) is preferable.

Specific examples of chromophores A and B include: (3, ffl is an integer between O and 2) 1 CH2Cl.

(+2.m is an integer of θ to 3) (Q, m, n are integers of O to 1), but is not limited to stiffness.

As a specific example of 1, (Q is an integer of O or 1) 7 8- Examples include, but are not limited to, the following.

Here, an example of the organic compound represented by the general formula (I) is one represented by the following formula (1).

This compound can be obtained, for example, by synthesizing compounds of the following formulas (2) and (3) in the presence of triethylamine and ethanol.

(3) The recording layer of the present invention may contain other dyes, such as pentaphthalocyanine, tetrahydrocholine, dioxazine, triphetchazine, phenanthrene, anthraquinone, as necessary, in order to improve recording characteristics and stability. (
Indanthrene) series, cyanine (merocyanine) series, croconium series, xanthine series, 1-heriphenylmethane series, pyrylium series.

Squarylium-based, azulene-based dyes, metals or metal compounds, such as In, Sn, Te, Bi, AQ
, Se, TaO2, 5nO5As, Cd, etc. may be dispersed or laminated.

The recording layer may be made of a polymeric material, an organic compound (aminium, immonium, diimmonium compounds, etc.) or an organometallic complex compound (bisdithiodiketone, bisphenyldithiol complex, etc.) that has absorption ability in the long wavelength range. You may mix and disperse low molecular weight compounds such as. Furthermore, the recording layer may also contain storage stabilizers (metal complexes, phenolic compounds), dispersants, flame retardants, lubricants, plasticizers, and the like. The thickness of the recording layer is 1.00 to 10 μm.
, preferably 200 people to 2 IJm. As a method for forming the recording layer, vapor deposition, CVD, sputtering, and solvent coating methods such as dip coating, spray coating, spinner coating, blade coating, roller coating, curtain coating, etc. can be used.

(4) Protective layer The protective layer (a) protects the recording layer from scratches, dust, dirt, etc., (b) improves storage stability of the recording layer, (c) improves reflectance, and (d) sensitivity. It is used for the purpose of improving. For these purposes, the materials listed above for the undercoat layer can be used. The protective layer may be a single layer or a laminate.

In the present invention, the undercoat layer and the protective layer may further contain a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, etc., as in the case of the recording layer. I can do it.

Further, in the undercoat layer and the protective layer, the general formula (I)
The compound shown in can be contained.

〔Example〕

The present invention will be further explained below with reference to Examples, but the present invention is not limited to these Examples.

(Example 1) A 1,2-diglolethane solution of the compound represented by the above formula (1) was applied with a spinner onto a polymethyl methacrylate plate (with pregrooves) having a thickness of 1°2cm and a diameter of 30nrn, and A recording medium was manufactured by providing a recording layer with a thickness of a human being. The spectral characteristics of this recording medium are shown in FIG.

(Example 2) A recording medium was obtained in the same manner as in Example 1 except that a compound represented by the following (4) was used instead of the compound represented by the L-formula (1).

11 2 (Comparative Example 1) A recording medium was obtained in the same manner as in Example 1 except that a compound represented by the following formula (5) was used instead of the compound represented by the above formula (1) (Comparative Example 2 ) A recording medium was obtained in the same manner as in Example 1 except that a compound represented by the following formula (6) was used instead of the compound represented by the formula (1). The spectral characteristics of this recording medium are shown in FIG.

The linear velocity of each recording medium produced as described above was 2.1 m.
/see, and semiconductor laser light with a wavelength of 790 nm was irradiated from the substrate side. The beam diameter of the laser beam used at this time at the writing point was about 1.3 μm. ]
, Recording was performed with a recording frequency of MHz and a recording power of 3d, and then the recorded information was reproduced with continuous light from the same semiconductor laser (power: 0.2mW), and a spectral analysis of the reproduced waveform (scanning filter bandwidth 30 K 11 z ) to measure C/N.

The amplitude of the reproduced waveform was also measured at the same time. The measurement results are shown in the table below.

Table 1 From Table 1, it can be seen that the recording media of Examples I and 2 have higher reflectance than the recording media of Comparative Examples 1 and 2, and also have less change in signal amplitude. When the recording media of Examples 1 and 2 were stored in an environment of 60° C. and 90% R1 for 2000 hours, the appearance of defects was investigated, and the increase in defects was found to be slight.

〔Effect of the invention〕

According to the present invention, the configuration allows high-sensitivity recording and high-contrast 1 reproduction at the same time using a single pick amplifier. Furthermore, it is possible to provide a highly reliable optical information recording medium that does not develop defects even under long-term storage.

[Brief explanation of drawings]

FIG. 1 is a graph showing the spectral characteristics of the recording medium of Example 1 according to the present invention, and FIG. 2 is a graph showing the spectral characteristics of the recording medium of Comparative Example 2.

Claims (1)

[Claims] (1) An optical information recording medium characterized by having a recording layer containing an organic compound represented by the following general formula (I) on a substrate. A-L-B (wherein A represents a chromophore having an absorption maximum near the recording/reproducing light wavelength, B represents a chromophore having a reflection maximum near the above wavelength, and L represents a substituted or unsubstituted alkylene group. .)